The objectives of the recently established Immune Monitoring Laboratory Shared Resource (IML) are: 1) to provide state-of-the-art immunoassays to allow NCCC clinicians to monitor the immune responses of patients enrolled in clinical trials; 2) to provide expert guidance in the choice and interpretation of immunoassays most relevant to a particular clinical trial; 3) to provide quality control by rigorous analysis of a reference population to define baseline responses as well as validation of the reproducibility of the result; and 4) to provide a resource for all NCCC Investigators to use various dedicated instruments not normally available in individual laboratories, e.g. ELISPOT reader, autoMACS, Luminex. A wide variety of services are available, from isolating cells and cell subsets to aliquoting and storing cells and serum. Assays include ELISPOT, tetramer staining, cell census proliferation assay, ELISA, multiplexed cytokine and chemokine assays, intracellular staining for cytokines, and cell subset analysis by flow cytometry. The IML can facilitate efforts of an investigator to examine and monitor various components and inter-relationships within the immune system from the planning stage of a study to data interpretation. This Resource broadens the range of services previously available to NCCC members and encourages collaborations. It provides consultation by the Director, invaluable protocol planning assistance, skilled staff, and up-to-date technology, and results in significant savings to users in time and costs.